Chemical heater for use in a system for generating gas from liquefied gas



De@ 1, 1942 w. H. GRINDLE 2,303,995

CHEMICAL HEATER FOR USE IN A SYSTEM FOR GENERATING GAS FROM LIQUEFIEDGAS Filed Sept. 8, 1941 5 Sheets-Sheet-l Dec. l, 1942. w GRlNDLECHEMICAL HEATER FOR USE IN A SYSTEM FOR GENERATING GAS FROM LIQUEFIEDGAS 3 Sheets-Sheet 2 Filed Sept.

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A y l Dec. 1, 1942. w. HJ/GRINBLE 2,303,995

CHEMICAL HEATER 'FOR USE IN A SYSTEM FOR GENERATING GAS FROM LIQUEFIEDGAS Filed Sept. B, 1941 3 Sheets-Sheet 3 rwa/Mofo S Wfl/iwf? /64 @1i/m79r www Patented Dec. 1, 1942 CHElVIICAL HEATER FOR USE 1N A SYSTEM FORGENERATING GAS FROM LIQUEFIED GAS William H. Grindle, Harlingen, Tex.Application September 8, 1941, Serial No. 410,020

10 Claims.

One of several defects in the ordinary liqueed petroleum gas plants isthe annoying habit of the pressure dropping to an extremely low pointwhenever a large vapor withdrawal load is placed on it. This usuallyhappens in the wintertime merely because of the fact that more heatingstoves and other appliances are being used. However, gas plant failuresare not uncommon even in summertime if the load is heavy, especially incommercial plants which are'furnishing gas vapor to gas engines, cottonand grain dryers, sterilizers, etc. This gas pressure failure isaccounted for by the fact that whenever any liquid is evaporated orvaporized, the process causes a cooling or refrigerating effect at thepoint of vaporization. In the case of a tank of liquefied petroleum gasin a gas plant, the vaporization point is over the entire surface of theliquid. As this process goes on, the liquid graduallybecomes colder andcolder until its temperature is reduced below its vaporization point.Even the tank itself and the surrounding earth (in the case of anunderground plant) becomes so cold that it cannot supply any more heatto vaporize the liquid within the plant. When this occurs a gas failureis evident and artificial heat must be applied if service is tocontinue.

Another defect in the ordinary gas plants'is the fact that where amixture of several liqueed gases are used, at periods when no vapors ."f

are being withdrawn the various gases stratify or seek diiferent levelsowing to their differentv specific gravities.

When this occurs, the B.A t. u. content of the vapors diifer on beingwithdrawn and cause another annoying condition to occur. As an example;suppose a cook stove was adjusted to a mixture of 30% propane (2519 B.t. u.) and 70% butane (3274 B. t. u.) or 'a combination value of 2765 B.t. u. The stove would burn sufficiently because it would be consumingexactly the right amount of air to produce the perfect name. VNowsuppose the stove is not in use for some time and the two liquidsstratify. When the stove is again lighted, it will blow and odor becauseit will be using the same amount of air but will be supplied with avapor with a B. t. u. value of somewhere near 2519Y B. t. u. Thereforethe ame will not be perfect nor efcient, because the burner will besucking in more L air than is needed for this value vapor. This hasoccurred because the propane being lighter has risen to the top of theliquid level'. This condi- -tion will continue to exist until the butaneis cause an unpleasant reached and then the burner will begin to smoke3;

because altho it is still using the same amount of air, it is now beingsupplied with a vapor somewhere near a 3274 B. t. u. value. In this casenot enough air is being supplied so all the vapor is not being consumedand the unburned portion is deposited on the bottom of the pan or kettlein the form of soot.

Therefore what is needed is a plant which will in addition to keeping upthe gas pressure also prevent the various gases from stratifying.

This invention relates to liqueed gas dispensing systems of the generaltype disclosed in my co-pending application Serial No. 300,471, ledOctober 20, 1939, which has matured into Lettersr Patent No. 2,256,591September 23, 1941, and among other objects contemplates the provisionof an automatically controlled heat exchange device for maintaining thepressure of the gas generated in a storage tank of the aforesaidmentioned system substantially constant in cold climates and under varyingweather conditions. More particularly, it is the principal object ofthis invention to provide a chemical heater in heat exchanging relationwith the liquefied gas of the system, the chemical heater beingactivated by water supplied thereto by means of a valve automaticallyoperated by a pressure trip device controlled in response to thepressure of the generated gas.

Another object of this invention is to provide in the gas generatingsystem of the type referred to above, a chemical heating device adaptedto met the rigid requirements of fire underwriters and avoid the dangerof an explosion and which chemical heating device furthermore is ofsimple design, eflicient in operation, economical and cheap tomanufacture.

With the foregoing and other objects in view, the invention resides inthe novel arrangement and combinationof p arts and in the details 0fconstruction hereinafter described and claimed, it being understood thatchanges in the precise embodiment of the invention herein disclosed maybe made within the `scope of what is claimed without departing from thespirit of the invention.

A practical embodiment of the invention is illustrated in theaccompanying drawings wherein:

Figure 1 is an elevational view with parts cutaway to show details ofconstruction of a preferred form of gas generating system with thechemical heating device.

Figure 2 is a cross-sectional view of the autoview on line 3-3,

view on line 4 4,

Referring to the drawings in detail Il) denotes a conventional form oftank which is adapted to contain a supply of liquefied petroleum gas II,the tank I being provided with a dome I2 housing the valves, regulators,governor and other devices for the control and delivery of the generatedgas which elements form no part of the present invention and hence arenot shown. The

tank I0 may be located either above or below the ground and may be ofany desired capacity.

Located on the bottom of the tank I0 directly beneath the dome I2 is atrap or dome I3 of inverted box-like form having the wall edges thereofat its open end abutting the tank bottom and preferably secured theretoby welding as at I4. The walls of the trap I3 adjacent the welded edgesthereof are provided with a plurality of openings I5 to permit theliquefied petroleum gas to enter the trap. Extending vertically from thetrap I3 is a heating well I8 having its lower end projecting into thetrap I3 and terminating but slightly from the bottom of the tank. Theheating well I8 is preferably formed of pipe stock of a relatively largediameter with its lower end, provided with xed and rigid end wall I9,which end wall, see Figure 5, is as indicated above slightly spaced fromthe bottom of the tank. The upper end of the heating well I8 is open andextends outwardly of the tank IU and into the dome I2 for a desireddistance. Preferably the upper end of the heating well should be solocated in the dome I2 as to be readily accessible, so as to permit theeasy placement therein and removal therefrom of the chemical heater tobe hereinafter described. Mounted on the open end of the heating well I8is a closure cap which is secured thereto by a threaded engagementtherewith. At the points where the heating well I8 extends through thetop wall 2| of the trap I3 and. the top wall 22 of the tank I3, theheating well is permanently secured thereto, respectively, as by thewelds 23 and 24, thus insuring a rigid and leakproof connection of theheating well.

Arranged to one side of the heating well I8 and parallel thereto is aspewing pipe 25, the lower end of which extends through the top wall 2|of the trap I3 for a slight distance below the same and the upper end ofwhich terminates a slight distance below the top wall 22 of the tank I0, so as to be above the level of the liquefied petroleum gas in thetank. see Figure 1. The space in the tank IIJ above the level of theliquefled petroleum gas serves as a reservoir for the generated gaswhich is supplied to the point of use through the delivery pipe 2E, inthe manner well known. The spewing pipe 25 is open at both ends, seeFigure 5, and is welded to the top wall 2| of the trap I3 as at 21 toeffect a rigid and leak proof connection. A brace 28 supports the upperend of the spewing pipe 25 by connecting the same to the heating wellI8.

Located at the bottom of the heating well I8 is the chemical heater 3Uwhich comprises a cylindrical container 3| formed of anon-corrosivematerial such as Pyrex glass, porcelain, 75

hard rubber, etc., open at its top and provided with a removable plugcap 32 secured thereto as by a threaded engagement with the inside wallof said container. Superposed above, the plug cap 32 is an insulatingcap 33 comprising upper and lower metal discs 34, 35 and an intermediatedisc of insulating material 36 such as asbestos, the complete insulatingcap 33 having a diameter such as to slidably engage the insidecylindrical wall of the heating well I8. The insulating cap 33 andjuxtaposed plug cap 32 are xedly mounted on the lower end portion of awater pipe 31, being retained in xed relation thereto by the clampingcollars '3B-39, the connection being such as to be positively leak-proofboth against water and the gases generated in the chemical container 3|.'I'he water pipe 31 at its upper end extends axially through the heatingwell closure cap 20 and is similarly secured thereto by clamping collars40-4I, the terminal end of the water pipe 31 having fixed thereto asection 42 of a pipe union fitting 43.

The chemical container 3| is of cylindrical form and of an externaldiameter such as to provide for but slight clearance between the sameand the inside wall surface of the heating well I8, as clearly shown inFigure 5. Furtherinorethe container 3| is suspended from the end of thewater pipe 31 by Virtue of its connection to its plug cap 32, and is ofsuch a length that the bottom of the container is but slightly spacedfrom the bottom wall I9 of the heating well. Preferably the arrangementof the container mounting is such that the insulating cap 33 thereoflies in the plane of the top wall 2| of the trap I3 whereby the chemicalcontainer 3| will lie wholly within the trap I3, albeit confined withinthe heating well I8, see Figure 5. The heat thus generated by thechemical heater 38, in the manner as will be hereinafter described, isdirected entirely within the trap I3 and is prevented from escapingupwardly of the heating well by the insulating cap 33.

Suitably located within the dome I2 is a double acting valve mechanism45 and a pressure controlled trip 46 for operating the same. The valveand trip mechanism is shown in de'- tail in Figure 2. The double actingvalve comprises a housing 41 formed to provide cylindrical ends 48 and49, and a central enlarged chamber 5U. The valve housing end 48threadedly receives a plug 5I having an inner cylindrical portion 52snugly fitted in the bore 53 of a shoulder 54, the plug 5I compressingbetween the threaded portion thereof and shoulder 54, a packing 55.Extending outwardly from the threaded portion of the plug is a sleeve 56which threadedly receives one end of a Water pipe 51, the other end ofwhich carries the mating section 58 of the pipe union tting 43. Ifdesired the water pipe 51 may be formed of flexible tubing to facilitatehandling thereof when the union 43 is disconnected for effecting removalof the chemical container 30. In a like manner the other valve housingend 49 threadedly receives a plug 60 having an inner cylindrical portion6I snugly fitted in the bore 62 of a shoulder 63, the' plug 6|)compressing between the threaded portion thereof and shoulder 63, apacking 54. The plug 6I) is provided outwardly of the threaded portionwith a sleeve 65 having a lateral extension 66 and an axial boss 61.

The opposed faces of the cylindrical extensions 52 and 6I of the plugs5I and 60 are provided with co-axial frusto-conical valve seats 'I0 and1| respectively,. and extending' co-axially within the plugs are bores12 and 13, respectively. Slidably extendingv into the bores 12 and 1'3are the guide stems 14 and 15, respectively of a double valve 1E'comprising axially spaced frustoconical valves l1A and 18 adapted forseating engagement with the valve seats and 1|, respectively, connectedbyV a shank portion 19. Extending axially from the guide stem 15'is aguide. rod 8l!A which extends outwardly of the` boss 61. A cap 8|surrounds the guide rod 80 contains a packing 82, the cap 8|beingthreadedly mounted onthe boss 61'. Preferably the double valve. 1@

is machined as a single unit and the guide stems:

14 and 15 are each provided with a plurality of longitudinal grooves 8dandii, respectively, that extend from the valves 11, 13` to. theterminal` outer ends of said guide stems. Tnet-valves 1.1

and 18 are spaced apart a distance such that' when one valve is seatedon its seat the other valve will be spaced from its seat, as clearlyshown in Figure 2.

The lateral extension 68 of' plug 50. is provided with a passage 81communicating with the bore 13, and threadedly receives one end of awater.

supply pipe 88. Connected to the water chamber 50 is a vent pipe 80.Thus with thevalve 11' seated on its seat 1G, water' supplied from theVpipe 88 enters the chamber Eil through the passage 81, bore 13 andgrooves 85 in guide stem 15.

When valve 11 is uhseated, as will be hereinafter described, the othervalve 18 seats on. its seat 1| thus closing -oi the supply of water intothe chamberA 50, the water trapped in said chamber then escaping throughgrooves iill and bore-12' into water delivery pipe 51 to be conducted tochemical heater 30.

The double valve 19 is.' under the direct control of the pressurecontrolled trip indicated gener'.- ally by the reference character'ri551 Mounted within a casing 92 is a bell-crank lever' 935: having along arm S4 and a short arm 95. The short arm 95 engages a plungeril thelower end of which is connected to a piston ork diaphragm (not shown)adapted to be acted on bythe pressure of the generated gas in thepressure pipe 91 which extends from the casing 92 through the top wall22 of the tank l0 into the gas chamber' (above the level of theliclueiied` gas) therein. Thus, the movement ory theposit'ion4 of theplunger 96 is dependent on the pressure of the generated gas. A tensioncoil springA 58 rendered adjustable by the screw 99 is connected to theupper end of the long arm S4.

The guide rod 80 extends into the casing 82 and has pivotally connectedthereto as at E00 one end of a latch I0 l, the other end of the latchbeing provided with inclined cam faces |02 and |03 arranged to beengaged by a pin |84 on the long arm 94. A coil spring` |05 acts to holdthe cam faces of the latch in engagement with the pin, movement of thelatch being limited by a` guide link |06. At high pressure the pin |534en.- gages the cam face IGS of the latch, which is moved to the leftclosing valve 11 and opening valve 18. At low pressure, the plunger 96drops; bell-crank lever 93 being moved tothey leftV by spring 98 so thatpin |514 then engages cam face |02, this movement pulling latch lll totheright to open Valve 11 and close valve 18. The position of the partsshown in Figure 2 is that for low pressure. Movement of the bell-cranklever 93 provides for a trip action on the. latch 50i, the pin |04riding on. the cam faces |82 and H33 tripping the latch tomove theIsame-to a left -or right position.

The chemical container 3| is filled (not completely) with any chemicalcompound or mixture |01: that will generate heat when Water is addedthereto. One such mixture is made up of 84% iron filings, 10% manganesedioxide and 6% sodium chloride. This mixture when dampened with a smallamount of water generates approximately centigrade of heat. The chemicalcontainer 3| should be of such a size as to hold a. quantity of such achemical mixture sumcient to generate heat through many cycles of low tohigh' pressure of the generated gas.

In cold'v climates an anti-freeze such as alcohol may be added to thewater suppliedv to the valve reservoir 50. This will not interfere with.the chemical reaction and will prevent the Water from freezing.

The operation of the chemicalv heater, double acting valve and pressurecontrolled trip is` apparent from the above description and briefly isas follows:

When the pressure of the generated gas is low, the pressure iscorrespondingly reduced in the pressure pipe 91 to the piston ordiaphragm (not shown) of the plunger 95 which drops allowing the spring98 to pull the bell-crank lever 93 to left pin |04 being in engagementwith cam face |03. This movement of bell-crank lever 93 to left willmove latch lill to'the right as it is snapped into position when thep-in mil engages cam face |02. At this position double valve is moved toright closing water supply valve 18 and opening water delivery valve 11permitting water in valve reservoir 50fto trickle through grooves 84and` bore 12; water pipes 51 and 31 to chemical container 3 whereinresulting chemical reaction will generate heat causing the liqueiied gasto vaporize and buildup a pressure within the tank. Increase in gaspressure is transmitted through pressure pipev 91 to piston or diaphragm(not shown of plunger 96 which upon a predetermined increase willelevate plunger 90 and turn bell-crank lever Sil'to right againsttension of coil spring 98 causing latch 50| lto snap to left as pin' |04engages cam face |63. This movement will move double'valve to leftclosing water delivery'valve 1,1 and opening water supply valve 18,thusv letting water from water supply pipe 88: trickle into valvereservoir 5E!- through passage 81, bore 13 and grooves 85, whereby thedevice is ready for the next cycle which will begin Whenever the gaspressure in the tank is reduced to a predetermined point causingtripping device to again snap into position allowing water from valvereservoir to trickle into chemical container.

In tank it" the liqueiied gas cwsinto the trap i3 through the bottomopenings l5 and lills the saine- Whenever any gas (vapor) is drawnfromabove theliquid level the liquelied gas within the trap vaporizesandAbeing trapped, the vapor pressure Within. the: trap. forces theliquefied gas from within.v the trap.. up through the spewing pipe 25Awhere it further vaporizes .and mixes with' the surrounding vapor andthe rest oi the lidueedV gas falls back to mix with the main body of theliqueed gas thus preventing stratifying of the generated gas (vapor)This process goes on as long as any gasis withdrawn from the tank lllregardless of whether the chemical device is generating heat. I-Icweverwhen heat is. produced., the spewing action? becomes much more vigorousdue to the fact that the liquefied gas within the trap is vaporizingfaster.

Having thus described and illustrated'the invention. what is claimed asnew is:

l. In a system for generating gas from liqueiied gas, a tank, a trap inthe tank at the bottom thereof provided with perforations adjacent saidtank bottom, a heating well traversing said tank and projecting intosaid trap, a chemical heating device mounted in said well and located inthe portion thereof projecting into said trap, and a liquefied gasspewing pipe rising from said trap and terminating near the top of saidtank.

2. In a system for generating gas from liquefied gas, a tank, a trap inthe tank at the bottom thereof provided with perforations adjacent saidtank bottom, a heating well traversing said tank and projecting intosaid trap, a pressure controlled chemical heating device renderedfunctionally operative by a supply of water thereto mounted in said welland located in the portion thereof -projecting into said trap, and aliquefied gas spewing pipe rising from said trap and terminating nearthe top of said tank.

3. In a system for generating gas from liquefied gas, a tank. a trap inthe tank at the bottom thereof provided with perforations adjacent saidtank bottom, a heating well traversing said tank and projecting intosaid trap, a chemical heating device mounted in said well and located inthe portion thereof projecting into said trap, a water reservoirconnected to said chemical heating device, valve means for controllingthe entry and discharge of water from said reservoir and a tripmechanism for operating said valve means responsive to pressurevariations of the generated gas whereby to control the delivery of Waterto said reservoir and to said chemical heating device, and a liquefiedgas spewing pipe rising from said trap and terminating near the top ofsaid tank.

4. In a system for generating gas from liquefied gas, a tank, a trap inthe tank at the bottom thereof provided with the perforations adjacentsaid tank bottom, a heating well traversing said tank and projectinginto said trap, a chemical heating device mounted in said well andlocatedin the portion thereof projecting into said trap, a valve housingincluding a reservoir,

conduit means admitting water to said reservoir,

conduit means delivering water from said reservoir to said chemicalheating device, separate valve means for controlling the admission anddischarge of water into and out of said reservoir, and a trip mechanismfor operating said valve means responsive to pressure variations of thegenerated gas such that when the discharge valve is open to deliverwater from the reservoir to the chemical heating device the admissionvalve for admitting water to the reservoir is closed and vice versa.

5. In a system for generating gas from liquefied gas, a tank containingsaid liqueed gas to a predetermined level providing a chamber thereabovefor the accumulation of the generated gas, a trap in the tank at thebottom thereof provided with perforations adjacent said tank bottom, aheating well traversing said tank having its upper end projectingoutwardly of said tank and its lower end portion `projecting into saidtrap, a liqueed gas spewing pipe rising from said trap and terminatingnear the top of said tank and in said tank chamber, a chemical heatingdevice comprising a container positioned at the bottom of said heatingwell and within said trap, a water delivery pipe extending axially intosaid heating well and suspending said container therein, a double valvehousing including a Water reservoir to which said water delivery -pipeis connected, a water supply pipe connected to said reservoir, areciprocating double valve in said valve housing arranged to alternatelyclose off said water delivery and water supply pipes, and a pressurecontrolled trip mechanism for operating said reciprocating double valveresponsive to predetermined low and high pressures of the generated gasin said tank chamber.

6. In a system for generating gas from liqueed gas, a tank containingsaid liquefied gas to a predetermined level providing a chamberthereabove for the accumulation of the generatedV gas, a trap in thetank at the bottom thereof provided with perforations adjacent said tankbottom, a heating well traversing said tank having its upper endprojecting outwardly of said tank and its lower end portion projectinginto said trap, a liqueiied gas spewing pipe rising from said trap andterminating near the top of said tank and in said tank chamber, achemical heating device comprising a container positioned at the bottomof said heating well and within said trap, a water delivery pipeextending axially into said heating well and suspending said containertherein, a double valve housing including a water reservoir to whichsaid water delivery pipe is connected, a water supply pipe connected tosaid reservoir, a reciprocating double valve in said valve housingarranged to alternately close olf said water delivery and water supplypipes, and a pressure controlled trip mechanism for operating saidreciprocating double valve responsive tov predetermined low and highpressures of the generated gas in said tank chamber, said double valvehousing and trip mechanism being located exteriorly of said tank, saidpressure controlled trip mechanism comprising a pressure pipe eX-tending into said tank chamber, and a plunger connected to said tripmechanism operated by the pressure in said pressure pipe.

7. A chemical heating device for use in a system for generating gas fromliqueed gas'including a tank containing said liquefied gas comprising aheating well traversing said tank, a chemical container positioned atthe bottom of said heating well and adjacent the bottom of said tank, awater reservoir mounted exteriorly of said tank, a double valve meanscontrolling the admission of water into and the discharge of Water fromsaid reservoir, conduit means communicating said reservoir to saidchemical container, conduit means supplying water to said reservoir, anda pressure controlled trip mechanism for operating said double valvemeans responsive to predetermined low and high pressures of thegenerated gas in said system.

8. A chemical heating device for use in a system for generating gas fromliquefied gas including a tank containing said liqueed gas comprising aheating well traversing said tank, a chemical container'positioned atthe bottom of said heating well and adjacent the bottom of said tank, awater reservoir mounted eXteriorly of said tank, a double valve meanscontrolling the admission of Water into and the discharge of water fromsaid reservoir, conduit means communicating said reservoir to saidchemical container, conduit means supplying water to said reservoir, anda pressure controlled trip mechanism for operating said double valvemeans responsive to predetermined low and high pressures of thegenerated gas in said system, said heating well being closed at itsbottom and having its upper end open and extending outwardly of saidtank, a closure cap for the open end of said heating Well, a portion ofsaid conduit means delivering water to said chemical container beingfixed to said closure cap and extending axially into said Well, saidchemical container comprising a removable closure plug secured to thelower end of said conduit means such that said chemical container issuspended within said heating Well.

9. A chemical heating device for use in a system for generating gas fromliquefied gas including a tank containing said liquefied gas comprisinga heating Well traversing said tank, a chemical container positioned atthe bottom of said heating well and adjacent the bottom of said tank, awater reservoir mounted exteriorly of said tank, a double valve meanscontrolling the admission of water into and the discharge of water fromsaid reservoir, conduit means communicating said reservoir to saidchemical container, conduit means supplyingr water to said reservoir,and a pressure controlled trip mechanism for operating said double valvemeans responsive to predetermined low and high pressures of thegenerated gas in said system, a housing for said double valve meansshaped to integrally include said Water reservoir, said points ofadmission and discharge of water being oppositely and co-axiallydisposed and each defining a valve seat, said double Valve meanscomprising a valve at each end of a shank portion adapted to seat on anadjacent valve seat, a bore at each end of said housing co-axial withsaid valve seats, a guide stem provided with a plurality of longitudinalgrooves extending axially from each valve slidably extending into anadjacent bore, and a guide rod fixed to one guide stem operativelyconnecting said double valve means to said trip mechanism.

10. A chemical heating device for use in a system for generating gasfrom liqueed gas including a tank containing said liquefied gascomprising a heating well traversing said tank, a chemical containerpositioned at the bottom of said heating well and adjacent the bottom ofsaid tank, a water reservoir mounted exteriorly of said tank, a doubleValve means controlling the admission of water into and the discharge ofwater from said reservoir, conduit means communicating said reservoir tosaid chemical container, conduit means supplying water to saidreservoir, and a pressure controlled trip mechanism for operating saiddouble valve means responsive to predetermined low and high pressures ofthe generated gas in said system, a perforated trap positioned at thebottom of said tank into which the lower end portion of said heatingWell projects, said chemical container being disposed Wholly within saidtrap and insulating means at the top of said chemical container wherebysubstantially all of the heat generated by said chemical container isdirected into said trap.

WILLIAM H. GRINDLE.

